Optical methods such as absorptiometry, fluorescence, and surface plasmon resonance have long been explored for sensing glucose. However, these schemes have not had the clinical success of electrochemical methods for point-of-care testing because of the limited performance of optical sensors and the bulky instruments they require. Here, we show that an ultrasensitive optical transducer can be used for wireless glucose monitoring via a smartphone. The optical transducer combines oxygen-sensitive polymer dots (Pdots) with glucose oxidase that sensitively detect glucose when oxygen is consumed in the glucose oxidation reaction. By judicious design of the Pdots with ultralong phosphorescence lifetime, the transducer exhibited a significantly enhanced sensitivity by 1 order of magnitude as compared to the one in a previous study. As a result, the optical images of subcutaneous glucose level obtained with the smartphone camera could be utilized to clearly distinguish between euglycemia and hyperglycemia. We further developed an image processing algorithm and a software application that was installed on a smartphone. Real-time dynamic glucose monitoring in live mice was demonstrated with the smartphone and the implanted Pdot transducer.

Conventional photodynamic therapy is severely constrained by the limited light-penetration depth in tissue. Here, we show efficient photodynamic therapy (PDT) mediated by bioluminescence resonance energy transfer (BRET) that overcomes the light-penetration limitation. The photosensitizer Rose Bengal (RB) was loaded in biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles, which were then conjugated with firefly luciferase. Spectroscopic characterizations indicated that BRET effectively activated RB to generate reactive oxygen species (ROS). In vitro studies of the cellular cytotoxicity and photodynamic effect indicated that cancer cells were effectively destroyed by BRET-PDT treatment. In vivo studies in a tumor-bearing mouse model demonstrated that tumor growth was significantly inhibited by BRET-PDT in the absence of external light irradiation. The BRET-mediated phototherapy provides a promising approach to overcome the light-penetration limitation in photodynamic treatment of deep-seated tumors.

The dual-photosensitizer upconversion nanoplatform takes advantage of upconversion luminescence and generates singlet oxygen and free radicals for enhanced photodynamic therapy.